The U.S. Supreme Court has let stand a US$300 million patent infringement ruling against Microsoft, granting a victory Thursday to i4i, which filed the lawsuit back in 2007.

The legal battle already forced Microsoft to modify certain functionality in its Word application in 2009, when the U.S. District Court for the Eastern District of Texas ruled in favor of Toronto-based i4i and told Microsoft to stop selling Word in the U.S.

At issue was an i4i patent that covers technology that lets users manipulate the architecture and content of a document, which i4i alleged Microsoft infringed upon by letting Word users create custom XML documents. Microsoft removed the feature.

"This case raised an important issue of law which the Supreme Court itself had questioned in an earlier decision and which we believed needed resolution. While the outcome is not what we had hoped for, we will continue to advocate for changes to the law that will prevent abuse of the patent system and protect inventors who hold patents representing true innovation," Microsoft said in a statement.

The case has been closely watched by legal experts because Microsoft, backed by other major technology vendors like Google and Apple, had argued in favor of watering down the usual standard required for companies to successfully defend themselves from patent infringement accusations.

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